How to create a parabola by equations in NX10

Hi everyone,

Here is my problem :

I need to create a parabola with these equations :

X=t

Y=0

Z=t²/4*F

where " F " is the focal length (a value that I could change).

A tool already exists in NX (Curve -> More -> Parabola) but I have to create new curve everytime when I need to change the focal lentgth.

I would like to change just the paramater " F " in the " Part Navigator " to change the parabola shape.

Do you know if this is possible ?

Thanks in advance

Playmo31